In order to be able to design our new globally exponentially convergent flux observer, we add to the filtering technique of [1]}, [2]}, a novel mathematical concept: the creation of a virtual invariant manifold. Thanks to this new technique we are able to replace the gradient-based observer design by the high performance Kreisselmeier's regression extension (KRE)-based estimator, reported in [3]} for the design of adaptive observers for linear time-invariant (LTI) systems. We notice that the KRE-based estimator was recently used for electromechanical systems in [4]}—see [5]} for a detailed analysis of the properties of this estimator. To evaluate performance of the proposed sensorless observer for IPMSMs we present numerous simulation and experimental results.
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